Selective system



March 2-1, 1933. H. BURTON 1,901,867

SELECTIVE SYSTEM Filed Jan. 25, 1929 2 s t s t 1 28 g I} 2 k i u n INVENTOR March 21, 1933. H. BURTON 1,901,867

SELECTIVE SYSTEM Filed Jan. 25, 1929 Z'Sheets-Sheet. 2

STATIONI.

STATIONZ. I

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Patented Mar. 21, 1933 UNITED STATES HENRY BURTON, OF GARDENA, CALIFORNIA SELECTIVE SYSTEM:

Application filed January 25,1929. Serial No. 335,041.

My invention relates to a selector, of the step by step type, and the principal object of my invention is, to provide a selector of extreme simplicity adapted to'control electric circuits at remote stations for any purpose, but more particularly adapted to be used as a selective signal and lock-out device on party telephone lines.

'Existing apparatus of this kind requires special circuits, special central office equipment, and special operating technic.

My invention is peculiar in that it is, electrically, the equivalent of the usual telephone bell. It operates on existing circuits and is actuated by the ordinary ringing current, supplied by existing ringing machines and magnetos.

A further distinguishing feature of my invention is its ability to interpret the conventional signal code, so that no change in central office equipment or operating routine is necessary where the invention is applied as a selective signal on existing party lines.

My selector is an alternating or pulsating current machine, adapted to be used with condensers and connected in a circuit having a normal direct current potential such as a common battery telephone loop. Also, the

unique step up mechanism by which the power for each step is cumulative over a comparatively long period, makes practicable the operation of the selector on heavily loaded party lines where the ringing current is too feeble to actuate the conventional step up mechanism.

In describing my invention, reference is had to the accompanying drawings, in which:

Fig. 1 is a front sectional elevation.

Fig. 2 is a side elevation.

Fig. 3 is a plan of the assembled selector.

Fig. 4 is a diagram showing the action of one of the escapements.

Fig. 5 shows the action of a switch and selector.

Fig-6 is a diagram to show the action of another escapement.

Fig. 7 shows another form of switch and selector.

Fig. 8 is a partial side View showing the local connections of the circuits to be con trolled.

Fig. 9 is a. wiring diagram of a party telephpne line equipped with my improved soec or.

I Referring to Figs. 1, 2 and 3, a Wheel .10 is supported upon a shaft 11 which turns freely on point bearings. lVheel 10 has a comparatively heavy rim, provided with very fine ratchet teeth. The 'electro magnet 60 12 is the same as used in the regulation telephone ringer movement. The armature 13 is flexibly supported by the flat spring 14, slightly'away from the pole faces of the electro magnet 12. An extension of the armature carries the spring pawl 15 just out of the path of the ratchet teeth on the rim of the wheel 10,'as shown in Fig. 1.

The inner end of a coiled wire spring 16 (Fig. 3) is secured to the shaft 11, its outer end being held by pin 17 .on the frame. The spring 16 is so wound and tensioned as to rotate the shaft backward or counter-clockwise. The disks 18 and 19, rigidly fixedon shaft 11, are provided with oblique vanes, or spaced members. The vanes on .disk lS occupy about three-fourths of the periphery. The vanes on disk 19 are spaced closer toget-her and occupy about one-fourth of its periphery. The shaft 11 and wheel 10. constitute an oscillator.

The latches 20 and 21 are fleXiblysuppo-rted in the paths of the vanes or spaced .members of disks 18 and 19 respectively. The disk 18 and its vanes and the latch 20 and 35 its spring 23 constitute a step-up escapement for governing the advancement of the oscillator. The disk 19 and its vanes and-the latch 21 and its spring 23 constitute a time escapement forgoverning the time of retraction of the oscillator to its initial position. The shanks of these latches are identical. Near the lower end of the shank is crossmember, which bears in the bottom of a V-shaped pocket 22 in the frame. This pocket is slightly deeper than the cross member. At the extremelower end of the shank is attached one endof a coiled wire spring 23, the other end being attached to the frame directly below the center of pocket 22.

The position of the pocket and point of attachment of spring 23, is such that the latch is normally held tangent to the disk with which it cooperates, but will yield to the right or left or directly upward. The latch 20 has a triangular shaped head adapted to be moved to the left by the downward passage of an oblique vane of disk 18.

Just below the triangle is a step 24, so located as to intercept a vane, just after its upper edge passes the inclined face of the triangular head (as at 0, Fig. 4). The step 24 has a lip turned upward so as to catch the vane and hold the latch until the vane moves slightly upward.

The base of the triangular head has a downwardly turned hook 20a positioned so as to engage the upper edge of the vane when it moves upward and release on a slight downward movement of the vane (as shown at d, Fig. 4).

The head of latch 21 (see Fig. 6) has an inclined lip 21a projecting into the path of travel of the vanes of disk 19, and adapted to be moved to the right by the upward passage of a vane. Just above this lip is a step formed so as to engage the upper edge of a vane just after it passes the inclined lip 21a and release when the vane moves slightly downward. v

A crank pin or actuating member 25 is carried by an arm frictionally mounted on shaft 11, and this arm terminates in an index pointer and can be set on any point of the numbered dial on the face of disk 19.

The bell crank lever 26, 33 is fulcrumed as shown in Fig. 1 below and at right angles to the shaft 11. The horizontal arm 26 carries at its outer end a roller against which presses a leaf spring 27. The otherarm 33 is slightly offset and stands in the path of the crank pin or actuating member 28 carried by a disk 28a on shaft 11. On the arm 26 the latch 29 is yieldingly held by the coiled spring 30, vertical to arm 26 with its 1 upper end normally in the path of crank pin Just below the center of arm 26 is the'contact point 31, supported on, but insulated from, the frame by the insulating bushing 32, so positioned as to contact with arm 26 when the same is depressed. The arrangement of arm 26 and point 31 constitutes a simple single pole single throw switch.

Pin31 is one terminal and the frame of the selector the other terminal of the circuit to be controlled.

The switch just described, represents for the purpose of disclosure, the circuit controlling feature of my invention in its simplest form.

In practice any number of contacts may be operated by the arm 26 and as many arms 26 and cranks 25 as desired may be assembled along the shaft 11.

The selector comprises four distinct mechanisms. First a motor or driving mechanism, second an escapement or stepping mechanism, third timing mechanism, and fourth a switch or circuit controlling mechanism. The action of the various mechanisms will be considered in the order named. The action of the motor or actuating mechanism is as follows: The electromagnet 12 is energized by alternating or pulsating current the same as is ordinarily used to actuate the conventional telephone ringer. The armature l3 vibrates in unison with the pulsations of the current. At each downward motion of the armature the pawl 15 strikes the ratchet teeth on the rim of wheel 10 and urges it forward, or clockwise, against the torque of spring 16.

Due to the inertia of wheel 10 the rapid intermittent thrusts of the pawl 15 impart to it a uniform motion.

The motor shown and described is preferable when the selector is used for telephone switching in conjunction with existing telephone equipment inasmuch as it is electrically the equivalent of the existing telephone ringer, interchangeable therewith and operated by the same ringing current. However, any suitable motor or means for driving the wheel 10 may be substituted.

The action of the eseapement comprising the vane equipped disk 18 and latch 20 is clearly shown in Fig. 4. \Vhen ringing current is applied to the electromagnet 12, wheel 10 with shaft 11 and assembly, is driven forward until the first vane of disk 18 passes down over the triangular head of latch 20, forcing the latch to the left so that the step 24 is in the path of the vane and arrests its further progress, as at c, Fig. 4. So long as the ringing current continues and the wheel 10 is urged forward, the vane is held down on the step 24, the latch 20 cannot be restored because of the lip on step 24 and no further motion of the oscillator can occur.

When the ringing current is interrupted, the pawl 15 is held out of the path of the ratchet teeth by the flat spring 14. The retractor spring 16 revolves the shaft 11 backward, the vane moves upward, until it clears the lip on step 24; and the latch moves to the right until the upper edge of the vane is caught by the downwardly turned hook 20a on the head of the latch.

In this backward motion wheel 10 acquires a momentum suflicient to lift latch 20 against the tension of spring 23, as shown at (Z, Fig. 4. When the cross member on the shank of the latch stops against the top of the pocket 22, wheel 10 is definitely stopped and loses its momentum. Spring 23 then recoils, drawing latch 20 down to its bearing in the bottom of the pocket, which motion revolves the wheel 10 forward with force sufficient to carry the vane clear of the downwardly turned hook 20a. The latch is restored to its. normal position and the vane is free to move in either direction, as shown at b, Fig. 4. If it moves upward its inclined face will slide by the head of the latch which will yield to the right.

The time'interval required for the short oscillation as a vane passes through latch 20, is determined by the size and weight of wheel 10 and the torque of spring 16. \Vhen used in telephone signalling the parts are adjusted so that the oscillation requires about one second or the time interval usual between rings in party line code. If during this interval or before the oscillator has swung backward suflicient to carry the vane above the head of latch 20, ringing current is again applied to magnet 12, the oscillator will be again driven forward until the next succeeding vane impinges upon step 24, when another interruption of the ringing current will release the Vans as before.

It is evident that if ringing current be applied to magnet 12 and interrupted for short intervals, the oscillator will move forward one step at each application of ringing current. If the energizing current is interrupted for a considerably longer period the oscillator will swing back to the starting point. The disk 19 and latch 21 govern the rate of retraction of the oscillator during a part of its backward swing. Latch 21 offers no impediment to the forward rotation of disk 19, since the oblique vanes'slide down past the inclined lip and force the latch to the left out of their path (I) Fig. 6). Disk 19 is so positioned on shaft 11 with reference to disk 18, that when advanced the segment carrying vanes will have just passed the head of latch 21 when the first vane of disk 18 contacts with step 24.- of latch 20.

On its return swing the oscillator moves freely with constant acceleration until the first vane of disk 19 impinges upon the underside of the inclined lip 21a of latch 21 and slides it to the right so that the vane is arrested by the step at the top of the latch (as at 0, Fig. 6.).

In its backward rotation, wheel 10 acquires momentum SlllllClGIlt to lift the latch 21 against the tension of its spring, the recoil ofw-hich reverses the motion and the vanerebounds from latch 21,-which is then restored to its normalposition and the'action is repeated for each succeeding vane-of disk 19. The oscillator finishes its backward swing in a series of short oscillations. The total time required for the oscillator to complete a backward swing from any point of its arc is determined by the number of vanes of disk 19 required to pass latch 21 before crank pin 28 impinges upon arm 33, which is in turn determined by the angular position of pin 28 with reference to the vanes of disk The operation of the circuit controlling mechanism is as follows:

Referring to Fig. 5 the switch arm 26 is normally held in raised or open circuit position by the spring 27, the lip of which presses below the center of the roller. The crank pin 28 bears against the arm 33 which prevents the shaft 11 from rotating counter clockwise. N ow if the shaft 11 is revolved forward or clockwise, the crank pin 25 will deflect latch 29, as shown in dotted lines, to the left. At this point the latch 29 forms a link connecting the crank pin 25 with the arm 26, so that if the motion of shaft 11 is reversed'the backward swing of the crank 25 depresses the switch arm 26 until the lip of spring 27 bears above the center of the roller and presses the switch arm into contact with point 31. As the crank pin 25-0011- tinues to travel backward it disengages the latch 29 which is restored by the spring 30. On completion of the backward rotation of shaft 11 crank pin 28 impinges upon the underside of arm 38 to restore arm 26 and stop the shaft 11, with crank 25 in its original position.

If the forward rotation of shaft 11 is continued so that pin 25 travels beyond the point of latch 29, the latch is immediately restored by spring 30 and the subsequent backward swing of pin 25 only deflects the latch as shown in dotted lines to the right, and does not depress arm '26. The length of the are over which pin 25 must move in order to actuate the switch'arm 26 is determined by the ang-ular position of crank 25 with reference to pin 28. Crank 25 may be setat any point of the numbered dial, the divisions of which correspond to the vanes of disk 18.

If the index pointer is set at number 1 of the dial and the oscillator rotated forward until one vane of disk 18 passes the head of latch 20, stops on the step 24 and then returns to the starting point, the switch arm 26 will be first depressed into contact with point 31 and then restored to normal position when the oscillator finishes its back ward swing. The angular position of pin 28 relative to the vane segment of disk 19, governs the time the circuit controlled by the switch 26 will remain closed. If the index pointer is set on, say number 3, of the dial the oscillator must bemoved forward until exactly three vanes of disk 18 have passed latch 20 and then be returned to the starting point in order to operate switch arm 26. If the oscillator'is revolved a lesser distance forward pin 25 will not have reached the latch 29. g If it is revolved a greater distance pin 25 will have passed the latch. In either event the switch will not be operated.

It will be seen that if a number of switches are arranged side by side each havin a crank pin 25 carried on shaft 11 at a di erent angular position, then any particular switch of the group may be operated by revolving the oscillator the proper number of steps forward and allowing it to be retracted by spring 16.

To selectively operate switches at different stations a selector is placed at each Stilfi tion. Each selector has its crank pin 25 set at a different dial position, the selectors are electrically connected together and their oscillators stepped forward in synchronism. The number of steps the oscillators are stepped forward before they are allowed to return to normal determines which of the several selectors will operate its switch.

The conventional party telephone line has a pair of ringer coils connected directly across the line at each station as shown at station 1, Fig. 9. A code of signals is agreed upon, usually consisting of one ring for station No. 1, two rings for station No. 2, three rings for station No. 3, etc. All bells of course ring whenever ringing current is impressed upon the line, and each subscriber is expected to recognize his particular code ring and act accordingly.

The objections to this method of signalling are so obvious and well known as to require no exposition here.

Station 2, Fig. 9, illustrates the wiring connections of my invention as applied to a party telephone line on which the signal must be repeated within approximately five seconds. The coils of magnet 12 are connected directly across the line in place of the ordinary ringer coils. The regular ringer coils are connected from one side of the line to contact point 31. Switch arm 26 is connected to the opposite side of the line so that the ringer circuit is normally open, being connected across the line only when switch arm 26 is depressed into contact with point 31. Now when ringing current is impressed upon the line, magnet 12 will be energized and the oscillator stepped forward one step at each impressed ringing impulse, but the ringer circuit being open the bell will not ring.

If the impressed signal consists of exactly two rings switch arm 26 will be depressed, the bell circuit will be closed and will remain closed until the oscillator completes its backward swing, which, owing to the five seconds required for the vanes of disk 19 to pass latch 21, will not occur before the signal is repeated.

On repetition of the signal the ringing current will energize the bell coils and the bell will ring. Magnet 12 will also be ener-' gized and the oscillator again stepped forward so that the bell will ring at each repetition of the signal occurring at five second naogsev intervals. Vhen the ringing is definitely discontinued the oscillator will swing back to its starting point, open the bell circuit and the bell at this station will not again ring until exactly two rings are impressed upon the line. Each station may be'equipped with a selector similarly connected and each selector set to respond only to its particular code signal. This arrangement is particularly suited to systems equipped for automatic ringing.

Station 3, Fig. 9, shows my invention adapted to a party line on which the signal is not required to be repeated. In this case the connections of magnet 12 and the operation of the machine are the same as for station 2. The polarized bell is replaced by an ordinary vibrating bell or other signal operated by alocal battery or other source of energy controlled by switch 26, as shown. When the proper number of rings are impressed upon the line in the usual manner the machine at station 3 closes the local circuit and'the bell is caused to ring until the oscillator returns to normal and opens the circuit. The duration of the signal is determined by the adjustment of pin 28 as hereinbefore described.

The switch which has been described and which is shown in Fig. 5 is normally open and can be closed only temporarily by the operator. Fig. 7 shows a switch capable of being either opened or closed at the will of the operator by means of prearranged code signals. Referring to Fig. 7 the switch arm 35 is similar to the arm 26. The contact point 36 is supported in an insulating bushing in the frame and contacts with the arm 35 when same is depressed. The latch '37 flexibly supported on arm 35 is similar to latch 29, the only difference being the arm which carries the pin 38 adapted to fulcrum on the post 39 and. raise the arm 35 whenever the latch is deflected as shown in dotted lines to the left.

The crank pins or actuating members 40 and ll are carried by arms or disks'on shaft 11 and cooperate with the latch 37 in the same manner as the pin 25 cooperates with latch 29.

It will be observed that the closing of the switch 35 is accomplished in the same manner as the closing of switch 26, namely, by

the action of a crank pin in the fork of the latch 37 at the beginning of a backward swing of the oscillator, but whereas switch 26 is automatically opened on completion of the backward swing of the oscillator, switch 35 will remain in whichever position it is placed, because it has no member corresponding to arm'33 of Fig. 5.

If the machine is operated and the oscillator is rotated forward so that pin 40 deflects latch 37 to the left the arm 35 will be raised and the circuit opened, because one ring upon the line.

downward movement of pin 38 being prevented by post 39, it acts as the fulcrum for a bent lever of the second class, arm 35 being the weight and pin 40 the power. If the amplitude of the oscillation is such that .pin 40 is in the fork of the latch 37 at the beginning of the return swing latch 37 acts as one member of a toggle joint so that the arm will be again depressed and the circuit will remain closed until the machine is again operated to open it. If the oscillation carries pin 40 past the point of latch 37 its return swing will'only deflect the latch to the right upward movement of pin 38 being unopposed no downward pressure will be exerted upon arm 35 and the circuit will remain open until the machine is operated to close it.

Fig. 8 shows how a number of switches of either or both constructions are. arranged to be operated by the same oscillator. Fig. 8 also shows the wiring connections or" my invention when used as a combination selective signal and look-out for a party line telephone.

Assume the telephone station 3, Fig. 9, to be equipped with a machine having the switch 35 in addition to the switch 26, as shown in Fig. 8. The talking circuit is wired through switch 35 so as to be opened or closed thereby, otherwise the apparatus and wiring is the same as hereinbefore described. The crank pin 40 is positioned on shaft 11 so as to be moved into the fork of latch 37 when one ring is impressed upon the line. Crank pin 41 is positioned so as to be moved into the fork of latch 37 when exactly three rings are impressed on the line. Thus it will have the same angular position as pin 25.

Now, supposing station 2 to be signalled; the oscillator at station 3 is stepped :t'orward two steps. At the first ring pin l0 impinges upon latch 37, raises arm 35 and opens the talking circuit of station 3. The next ring moves pin 40 beyond the point of latch 37 so that its return swing will not depress arm 35 and the talking circuit remains open. When the conversation with station 2 is finished the operator impresses The oscillator is stepped forward one step, pin 40 engages the latch 37 and on its return swing depresses arm 35 and again connects the talking circuit to the line.

If station 3 is signaled the oscillator steps forward three steps arm 35 is raised as described, pin 25 engages the latch 29 and pin 41 engages latch 37 the return swing depresses both arms 26 and 35 the signal bell is operated as hereinbefore described, and the talking circuit remains connected to the line.

If each station on a party telephone line is equipped with a machine as above described the pin 40 of each machine is set so as to close switch 35 on the usual clear signal of one ring and to open its switch 35 on a signal consisting of any other number of rings. The pins 41 and 25 are set to correspond to the code signal of the station with which the machine is connected. lVhen any station is signalled the talking circuits of all other stations will be disconnected. lVhen the conversation is finished and the clear signal of one ring is impressed upon the line all stations will be again connected.

I claim as my invention:

1. A signal system comprising in combination a plurality of stations to be signalled, transmission means including a circuit common to said stations, means for impressing upon said common circuit a special current of pulsation character to form code signals, signal means associated with said stations normally disconnected from the common circuit adapted to be actuated by said special current therein when connected therewith, selector mechanism associated with each sig-. nal means permanently connected to the common circuit responsive only to said special current therein, adapted to connect its associated signal means to the common circuit in response to a predetermined number of applications of said special current at apredetermined time after cessation thereof to automatically return to its normal state and disconnect its signal means. from the common circult at another predetermlned' time after cessation otfthe special current therein.

2. In combination, a selector comprising an oscillator oscillatable in a fixed path from and to a normal position, retractor means of force so proportioned to the mass of said oscillator as to effect substantially retarded retraction thereof whenever said oscillator is advanced from its normal position and released, driving means responsive to code signals each signal identified by a particular number of power periods recurring at short intervals, a longer cessation of power marking completion of a signal, effective to exert substantially continuous and cumulative driving effort tending to advance the oscillator for the duration of each recurring power period and to permit retraction of the oscillator concurrent with each lapse of power, means automatically effective to arrest at predetermined stages the continuous advancement of the oscillator, adapted to release upon a slight retraction thereof, whereby the net advancement of the oscillator is progressive by overlapping oscillations when the time between power-periods is less than the tinieot' retraction of the oscillator from an advanced stage to :the

next preceding stage and the oscillator is completely retracted during the long cessation of power marking completion of a signal and switch means adapted to be actuated by the advancement and retraction of the oscillator.

A selectorcomprising in combination an oscillator oscillatable in a fixed path from and to a normal position, retractor means of force so proportioned to the mass of said oscillator as to effect substantially retarded retraction thereof whenever said oscillator is advanced from its normal position and released, driving means responsive to code signals, each signal identified by a particular number of power periods recurring at short intervals a longer cessation of power marking completion of the signal, effective to exert substantially continuous and cumulative driving effort tending to advance the oscillator for the duration of each recurring power period and to permit retraction of the oscillator concurrent with each lapse of power, a series of spaced members moveable with the oscillator adapted to follow each other in a common path of travel, latch means including a head oblique to and normally intersecting at a fixed point thereof said common path of travel, yieldable to the passage of the spaced members in the direction of their retreat, a step and a hook normally out of and adapted to be moved into said path of travel by each successive coaction of the oblique head wit-l1 each advancing spaced member so as to arrest the advance of said spaced member its retreat, incident to a lapse of driving effort, being in turn arrested by the hook, resilient means effective to cause each so arrested spaced memher to rebound from said hook upon impact therewith and to restore the latch means and switch means adapted to be actuated by the advancement and retraction of the oscillator.

4. In combination a selector, comprising an oscillator biased to a normal position oscillatable in a fixed path from and to said normal position, an electromagnet, means effective to excite therein for recurring periods vibratory magnetic flux, said recurring periods being grouped to form code signals, an armature vibratable in response to said vibratory magnetic flux, means whereby the vibrations of said armature are cumulative to exert substantially continuous driving effort tending to advance the oscillator from its normal position for the duration of each said recurring period and to permit retraction of the oscillator concurrent with each lapse of said magnetic flux, means antomatically effective to arrest at predetermined stages continuous advancement of the oscillator adapted to release upon a slight retraction thereof, means effective to so retard said retraction that the net advancement of the oscillator is progressive by overlapping oscillations when the driving periods recur at short intervals and the oscillator is automatically restored during cessation of driving effort upon completion of a signal and switch means adapted to be actuated by the advancement and retraction of the oscillator.

5. In a selector the combination comprising an oscillator having a normal position and a series of defined other positions, means effective to advance said oscillator from its normal position step by step responsive to code signals to any selected one of said defined other positions and to release said oscillator thereat, means effective to restore the oscillator when released and switch means including an actuating member movable with the oscillator and a latch normally intersecting at a selected point thereof the path of oscillation of the actuating member yieldable in both directions to the passage of said member adapted to coact therewith to actuate the switch means whenever the oscillator is advanced to aposition whereat said actuating member is in cooperation with the latch and is then retracted a predetermined minimum distance.

6. In a selector, the combination comprising an oscillator having a normal position and a series of defined other positions, means effective to advance said oscillator from its normal position step by step responsive to code signals to any selected one of said defined other positions and to release the oscillator thercat, means effective to. restore the oscillator when released and switch means including a first actuating member movable with the oscillator and a latch normally intersecting at a selected point thereof the path of oscillation of the first actuating member yicldable in both directions to the passage of said member adapted to coact therewith to actuate the switch means whenever the oscillator is advanced to a position whereat said first actuating member is in cooperation with the latch and is then retracted a predetermined minimum distance less than to its normal position, a second actuating member movable with the oscillator and a member intersecting the path of travel thereof adapted to cooperate therewith to restore the switch means upon further retraction of the oscillator.

7. In a selector, the combination comprising an oscillator having a normal position and a series of defined other positions, means effective to advance said oscillator from its normal position step by step responsive to code signals to any selected one of said defined other positions and to release the oscillator thereat, means effective to restore the oscillator when released and switch means including a first actuating member movable with the oscillator and a latch nor mally intersecting at a selected point thereof the path of oscillation of the first actuating member yieldable in both directions to the passage of said member adapted to coact therewith to. actuate the switch means whenever the oscillator is advanced to aposition whereat said first actuating member is in cooperation with the latch and is then retracted a predetermined minimum distance less than to its normal position, a second actuating member movable with the oscillator, a member intersecting the path of travel thereof adapted to cooperate therewith to restore the switch means upon further retraction of the oscillator and means effective to prolong and to determine the period of said further retraction.

8. In a selector the combination comprising an oscillator having a normal position and a series of defined other positions, means effective to advance said oscillator from its normal position step by step responsive to code signals to any selected one of said defined other positions and to release the oscillator thereat, means eltective to exert constant effort tending to restore the oscillator when released and switch means including a first actuating member moveable with the oscillator and a latch normally intersecting at a selected point thereof the path of oscillation of the first actuating member yieldable in both directions to the passage of said member adapted to coact therewith to actuate the switch means whenever the oscillator is advanced to a position whereat said first actuating member is in cooperation with the latch and is then retracted a predetermined minimum distance less than to its normal position, a second actuating member moveable with the oscillator and a member intersecting the path of travel thereof adapted to cooperate therewith to restore the switch means upon further retraction of the oscillator, a series of spaced members movable with the oscillator adapted to follow each other in a common path of travel, a latch having a lip oblique to and normally intersecting at a predetermined point thereof said path of travel yieldable to the passage of the spaced members when the oscillator is advanced and a step normally out of and adapted to be moved into said path of travel by each successive coaction of the oblique lip with each retreating spaced member during said further retraction of the oscillator and resilient means effective to cause each spaced member to rebound from said step upon impact therewith and to restore the latch.

9. In a selector, the combination comprising an oscillator oscillatable in a fixed path from and to a normal position, means effective to advance the oscillator from its normal position to a selected other position and to release it t-hereat, retractor means efi'ective to exert constant effort tending to restore the oscillator, the degree of said efi'ort being predetermined with reference to the mass of the oscillator so as to predetermine its ate of acceleration when released, a series of spaced members moveable with the oscillator adapted to follow each other in a common path of travel, a latch having a lip oblique to and normally intersecting at a predetermined point thereof the path of travel of the spaced members, yieldable to the passage of said spaced members in the direction of their advance and a step adapted to be moved into said path of travel by each successive coaction of the oblique lip with each retreating spaced member during retraction of the oscillator, resilient means effective to cause each spaced member to rebound from said step upon impact therewith and to restore the'latch and switch means adapted to be actuated by the advancement and retraction of the oscillator.

10. A selector comprising an oscillator, an electro-magnet, means whereby said oscillator is advanced by said electro-magnet, means for retracting said oscillator, means for controlling the advancement of said oscillator, a circuit closer, means for operating said circuit closer, for closing a circuit, when the oscillator has been advanced a predetermined degree and means for operating said circuit closer to open said circuit when the oscillator is retracted to its initial position.

11. A selector comprising an oscillator, an electro-magnet, means whereby said oscillator is advanced by said electro-magnet, means for retracting said oscillator, means for controlling the advancement of said 0scillator, a circuit closer, means for operating said circuit closer, for closing a circuit, when the oscillator has been advanced a predetermined degree and means for operating said circuit closer to open said circuit when the oscillator is retracted to its initial position and means for governing the time of retraction of said oscillator.

12. A selector comprising an oscillator, an electro-magnet, means whereb 1 said oscillator is advanced by said electro-magnet, means for retracting said oscillator, means for controlling the advancement of said oscillator, a circuit closer, adjustable means for operating said circuit closer at different degrees of advancement of said oscillator for closing a circuit, and means for operating said circuit closer to open said circuit when the oscillator is retracted to its initial position.

13. A selector comprising an oscillator, an electro-magnet, means whereby said oscillator is advanced by said electro-magnet, means for retracting said oscillator, a stepup escapement for controlling the advancement of said oscillator, a circuit closer, means for operating said circuit closer at a predetermined degree of advancement of said oscillator for closing a circuit, a time escapement for governing the time of retraction of said oscillator, and means for operating said circuit closer to open said circuit when the oscillator is retracted to its initial position.

14. In combination, a circuit controlling means comprising a movable member, an electro-magnet, means for exciting in said electro-magnet vibratory magnetic flux, an armature vibratable in response to said magnetic flux, means whereby the vibrations of said armature are cumulative to exert substantially continuous driving efi'ort tending to move said movable member during excitation of the electro-magnet, and switch means associated with the movable member, adapted to be actuated by movement thereof.

In testimony whereof I afiix my signature.

HENRY BURTON. 

